How to use this image

All examples in this guide use the public image. If you've mirrored the repository for your own use (for example, to your Docker Hub namespace), update your commands to reference the mirrored image instead of the public one.

For example:

• Public image: dhi.io/<repository>:<tag>
• Mirrored image: <your-namespace>/dhi-<repository>:<tag>

For the examples, you must first use docker login dhi.io to authenticate to the registry to pull the images.

Start a jaeger-es-rollover instance

Replace <tag> with the image variant you want to run.

Print all available subcommands and flags:

docker run --rm dhi.io/jaeger-es-rollover:<tag> --help

The tool has three subcommands. Each takes the Elasticsearch URL as its only positional argument and exits when done:

jaeger-es-rollover init     http://HOSTNAME:PORT
jaeger-es-rollover rollover http://HOSTNAME:PORT
jaeger-es-rollover lookback http://HOSTNAME:PORT

There is no version subcommand.

Common jaeger-es-rollover use cases

Initialize Elasticsearch for rollover

Run init once before deploying Jaeger with use_aliases: true. For each index set (spans, services, dependencies) it creates the index template, the first numbered index such as jaeger-span-000001, and the -read and -write aliases pointing at it. Running it again is safe; existing indices and aliases are left in place.

docker run --rm \
  --network my-network \
  dhi.io/jaeger-es-rollover:<tag> \
  init http://elasticsearch:9200

Add --adaptive-sampling to include the sampling index set, --skip-dependencies to leave dependencies out, and --shards / --replicas to override the template settings.

Roll the write alias to a new index

Run rollover on a schedule. When the current write index meets the conditions, Elasticsearch creates the next numbered index and moves the -write alias to it, and the tool adds the new index to the -read alias.

docker run --rm \
  --network my-network \
  dhi.io/jaeger-es-rollover:<tag> \
  rollover --conditions '{"max_age": "2d"}' http://elasticsearch:9200

--conditions is passed to Elasticsearch as-is, so any rollover condition it accepts works, for example max_age, max_docs or max_size. The default is {"max_age": "2d"}.

Drop old indices from the read alias

Run lookback on a schedule to stop searching indices older than a window. It only edits the -read alias; the indices stay in the cluster until jaeger-es-index-cleaner deletes them.

docker run --rm \
  --network my-network \
  dhi.io/jaeger-es-rollover:<tag> \
  lookback --unit days --unit-count 7 http://elasticsearch:9200

--unit accepts minutes, hours, days, weeks, months or years.

Authenticate to a secured cluster

For a cluster with authentication enabled, supply credentials rather than embedding them in the URL:

docker run --rm \
  --network my-network \
  dhi.io/jaeger-es-rollover:<tag> \
  init \
  --es.username elastic \
  --es.password changeme \
  --es.tls.enabled \
  https://elasticsearch:9200

--es.token-file and --es.api-key-file are also available for token-based clusters. Only one authentication method may be configured at a time. If the cluster certificate is signed by a private CA, add --es.tls.ca /path/to/ca.crt.

Match a non-default index prefix

If Jaeger is configured with an index_prefix, pass the same prefix to every subcommand or the tool will manage the wrong indices:

docker run --rm \
  --network my-network \
  dhi.io/jaeger-es-rollover:<tag> \
  init --index-prefix jaeger-main http://elasticsearch:9200

Use --archive to manage the archive index set instead of the primary one.

Hand rollover to Elasticsearch ILM

With an ILM policy named jaeger-ilm-policy already created in the cluster, run init with --es.use-ilm so the templates reference the policy. Elasticsearch then rolls over and retires indices itself, and the rollover and lookback jobs are not needed:

docker run --rm \
  --network my-network \
  dhi.io/jaeger-es-rollover:<tag> \
  init --es.use-ilm http://elasticsearch:9200

--es.ilm-policy-name selects a different policy name. init fails if the policy does not exist.

Pass flags as environment variables

Every flag can also be set as an environment variable: upper-case the flag name and replace . and - with _. The upstream documentation uses this form:

docker run --rm \
  --network my-network \
  -e CONDITIONS='{"max_age": "2d"}' \
  dhi.io/jaeger-es-rollover:<tag> \
  rollover http://elasticsearch:9200

Run it on a schedule

init is a one-time job; rollover and lookback are recurring. As a Kubernetes CronJob:

apiVersion: batch/v1
kind: CronJob
metadata:
  name: jaeger-es-rollover
spec:
  schedule: "*/10 * * * *"
  jobTemplate:
    spec:
      template:
        spec:
          restartPolicy: OnFailure
          containers:
            - name: jaeger-es-rollover
              image: dhi.io/jaeger-es-rollover:<tag>
              args:
                - rollover
                - --conditions
                - '{"max_age": "2d"}'
                - http://elasticsearch:9200

Replace <tag> with the desired version.

Image variants

Docker Hardened Images come in different variants depending on their intended use. Image variants are identified by their tag.

• Runtime variants are designed to run your application in production. These images are intended to be used either directly or as the FROM image in the final stage of a multi-stage build. These images typically:

  • Run as a nonroot user
  • Do not include a shell or a package manager
  • Contain only the minimal set of libraries needed to run the app

• Build-time variants typically include dev in the tag name and are intended for use in the first stage of a multi-stage Dockerfile. These images typically:

  • Run as the root user
  • Include a shell and package manager
  • Are used to build or compile applications

• FIPS variants include fips in the variant name and tag. They come in both runtime and build-time variants. These variants use cryptographic modules that have been validated under FIPS 140, a U.S. government standard for secure cryptographic operations. For example, usage of MD5 fails in FIPS variants.

To view the image variants and get more information about them, select the Tags tab for this repository, and then select a tag.

Migrate to a Docker Hardened Image

To migrate your application to a Docker Hardened Image, you must update your Dockerfile. At minimum, you must update the base image in your existing Dockerfile to a Docker Hardened Image. This and a few other common changes are listed in the following table of migration notes.

The following steps outline the general migration process.

1. Find hardened images for your app.

   A hardened image may have several variants. Inspect the image tags and find the image variant that meets your needs.

2. Update the base image in your Dockerfile.

   Update the base image in your application's Dockerfile to the hardened image you found in the previous step. For framework images, this is typically going to be an image tagged as dev because it has the tools needed to install packages and dependencies.

3. For multi-stage Dockerfiles, update the runtime image in your Dockerfile.

   To ensure that your final image is as minimal as possible, you should use a multi-stage build. All stages in your Dockerfile should use a hardened image. While intermediary stages will typically use images tagged as dev, your final runtime stage should use a non-dev image variant.

4. Install additional packages

   Docker Hardened Images contain minimal packages in order to reduce the potential attack surface. You may need to install additional packages in your Dockerfile. Inspect the image variants to identify which packages are already installed.

   Only images tagged as dev typically have package managers. You should use a multi-stage Dockerfile to install the packages. Install the packages in the build stage that uses a dev image. Then, if needed, copy any necessary artifacts to the runtime stage that uses a non-dev image.

   For Alpine-based images, you can use apk to install packages. For Debian-based images, you can use apt-get to install packages.

Troubleshooting migration

The following are common issues that you may encounter during migration.

General debugging

The hardened images intended for runtime don't contain a shell nor any tools for debugging. The recommended method for debugging applications built with Docker Hardened Images is to use Docker Debug⁠ to attach to these containers. Docker Debug provides a shell, common debugging tools, and lets you install other tools in an ephemeral, writable layer that only exists during the debugging session.

Permissions

By default image variants intended for runtime, run as the nonroot user. Ensure that necessary files and directories are accessible to the nonroot user. You may need to copy files to different directories or change permissions so your application running as the nonroot user can access them.

Privileged ports

Non-dev hardened images run as a nonroot user by default. As a result, applications in these images can't bind to privileged ports (below 1024) when running in Kubernetes or in Docker Engine versions older than 20.10. To avoid issues, configure your application to listen on port 1025 or higher inside the container, even if you map it to a lower port on the host. For example, docker run -p 80:8080 my-image will work because the port inside the container is 8080, and docker run -p 80:81 my-image won't work because the port inside the container is 81.

No shell

By default, image variants intended for runtime don't contain a shell. Use dev images in build stages to run shell commands and then copy any necessary artifacts into the runtime stage. In addition, use Docker Debug to debug containers with no shell.

Entry point

Docker Hardened Images may have different entry points than images such as Docker Official Images. Use docker inspect to inspect entry points for Docker Hardened Images and update your Dockerfile if necessary.